So i am putting togather a weaker fuel saver square body truck. Just a 83 1/2 ton with NA 6.2, nv3500, 3.08 diffs and 31” tires.

I have read pretty much everywhere that you can use a np208 from a th400, and it “bolts right up”.....This is not the case.

Then i have read a np241 from a 88-91 k5 700r4 will work. But i cant find one of those.
Does anyone who has actually done it, know?

Thanks